This disclosure relates generally to IP-based telephony and more particularly to encrypting IP-based multi-party calls.
Dedicated messaging applications are a common method of online communication. Users use client devices, such as smartphones, to execute the messaging application in order to exchange messages with other users. Messaging applications allow users to send and receive text, images, videos, and other forms of media. One feature provided by some dedicated messaging applications is the ability to call other users of the messaging application. Users communicating via a call desire secure communications to ensure that third parties cannot eavesdrop on information being passed during the call.
However, a problem arises during group calling sessions including more than two users (also called “multi-party calls”). Users in a group calling session may enter or depart the session at any time. Standard encryption techniques may fail to ensure that users who leave an ongoing group call can no longer access the call. For example, in a call of three users, one user may depart the session early. The remaining two users continue to communicate via the call and have an expectation of privacy. However, the third user may still be able to eavesdrop on the call despite no longer being part of the calling session. This inability to secure a group calling session where users can join or leave the call at any time leaves such calls susceptible to eavesdropping by third parties or other forms of attack.